Usual Ductal Hyperplasia (UDH)


General

  • Usual Ductal Hyperplasia (UDH) is a proliferative breast disease consisting of a non-clonal heterogeneous population of cells that can occur within areas of FCC

  • Slightly increased risk (1.5-2x normal) for breast cancer if >4 layers of epithelial cells are present.



Histology

  • Multilayered epithelial cells (mixture of cell types) that nearly completely fill and expand the ducts/acini

  • Increased myoepithelial cells (spindled nuclei)

  • Overlapping/streaming nuclei of the myoepithelial cells and epithelial cells that form a vague fascicle

  • Irregularly shaped & peripherally located secondary lumens

  • NO ATYPIA of epithelial cells (no pleomorphism)

  • NO NECROSIS


  • Useful Stains

  • Normal ducts & lobules have a subset of ER-positive cells

  • Express a heterogeneous staining pattern with CK5/6; LMWCK & HMWCK (heterogenous cell population)

  • ADH is generally positive for LMWCK (red cytoplasm) but NEGATIVE for HMWCK (brown cyt. staining in ME cells) and CK5/6

  • Keep in Mind:

  • There is a big difference in calling something usual ductal hyperplasia (no increased risk for breast cancer) vs. atypical ductal hyperplasia or ductal carcinoma in situ (both have an inc risk for breast cancer). We will discuss more about ADH in the next post.

  • The clear presence of well defined ME layer is reassuring in calling something benign. However, the presence/absence of myoepithelial cells is not as valuable for intraductal processes since some intraductal carcinomas retain some degree of myoepithelial cells around the periphery; these ME cells are usually attenuated or partially lost in tumor cells.

When to call UDH

  • There is obvious apocrine metaplasia

  • Streaming of nuclei

  • HMW keratin (CK903; aslo called 34bE12) and CK5/6 are generally POSITIVE in UDH

  • Keep in mind that some invasive carcinomas express CK5/6 (have a basal phenotype; negative for ER/PR/Her2; more aggressive)

Summary

  • Heterogeneous population of cells- diff shapes & sizes

  • Multilayered epithelial cells that nearly completely fill and expand the ducts/acini

  • Secondary lumens are irregularly shaped & peripherally located

  • NO epithelial cell atypia (no pleomorphism)

  • Increased myoepithelial cells (spindled nuclei)

  • Overlapping/streaming nuclei of the myoepithelial cells and epithelial cells that form a vague fascicle


Continue to the next post to learn the criteria for calling "atypical" ductal hyperplasia.

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